Lab 1.5: Stimulating Active Transport

requires energy and is against a concentration gradient

The movement of sodium and potassium maintained by the Na+ -K+ pump requires?

antiporter

The sodium-potassium pump is classified as a(n)

3, 2

The sodium-potassium pump moves _____ sodium ions and _____ potassium ions simultaneously.

lipid insoluble

Solutes that require active transport for movement might be too large to pass or might be

The ATP was depleted.

Why would a sodium transport stop before the transport was completed?

There were more pumps for transport.

Why could the equilibrium for the solutes be reached earlier?

More ions were transported.

What happened to the ions when you increased the amount of ATP dispensed with the same concentration of sodium and potassium on either side of the membrane?

3 mM ATP

At what concentration of ATP were the sodium and potassium maximally transported?

Transport of the ions was faster.

What was the effect of adding more Na+ -K+ pumps to the simulated cell?

There was no change in the transport rate because glucose is transported independently.

Describe the effect of adding glucose carriers to the sodium and potassium transport.

Using the 9m sodium chloride inside the cell and 6mM potassium outside the cell had the fastest rate because it models the sodium potassium pump. As 3 sodium ions leave the cell, 2 potassium ions are transported in; this ratio is the same as the 9:6 used in the experiment.

Describe the significance of using 9 mM sodium chloride inside the cell and 6 mM potassium chloride outside the cell, instead of other concentration ratios.

There was no sodium transported, even though ATP was present. For the sodium potassium pump to work, both ions (soodium and potassium) must be present for the exchange to work, and potassium was not present.

Explain why there was no sodium transport even though ATP was present. How well did the results compare with your prediction?

The addition of glucose carriers had no effect on sodium or potassium transport because the potassium and sodium ions move through primary active transport. Glucose carriers move glucose molecules across the membrane so the sodium and potassium ions will not be affected.

Explain why the addition of glucose carriers had no effect on sodium or potassium transport. How well did the results compare with your prediction?

Glucose is transported by facilitated diffusion. It does not require energy because the concentration of glucose is higher in the blood than in the cell. It moves from a high to low area because of the concentration gradient.

Do you think glucose is being actively transported or transported by facilitated diffusion in this experiment? Explain your answer.

glucose

example of non penetrating solute?

urea

example of penetrating solute?